Apparatus for and method of producing metal powders and metal strips



1957 'J. B. BR NAN ,81 ,826

. APPARATUS FOR AND METH 0F PRODUCING METAL POWDERS AND METAL STRIPSFiled Nov. 4,, 952 2 Sheets-Sheet 1 INVEN TOR. JOSEPH B. BRENNAN maommATTORNEYS 1957 J. B. BRENNAN 2,816,826

APPARATUS FOR AND METHOD OF PRODUCING METAL I POWDERS AND METAL STRIPSFiled Nov. 4, 1952 2 Sheets-Sheet 2 INVENTORL' w JOSEPH B. BRENNAN MWMATTORNEYS APPARATUS FOR AND METHOD OF PRODUCING METAL POWDERS AND METALSTRIPS Joseph B. Brennan, Cleveland, Ohio Application November 4, 1952,Serial No. 318,616

13 Claims. (Cl. 75-05) This invention relates to the production of metalpowders and metal strips, especially to apparatus for and methods ofproduction of iron and nickel powders and strips from their metalcarbonyls, and to a process of precisely atomizing metallic substancesand accurately, directionally projecting them by a centrifuge action.

This application is a continuation-in-part of my copending applicationSerial No. 722,829, now Patent No. 2,616,165, wherein I disclose thatmetal can be deposited on temperature controlled filaments when suchfilaments are exposed to vapors of metal carbonyls. The metal carbonylsdecompose at relatively low temperatures and this facilitates obtainingmetal deposits without the use of high temperatures as are required toproduce metal deposits from molten metal.

This application is also a continuation-in-part of my earlierapplication Serial No. 43,881 filed August 12, 1948, now Patent No.2,639,490 granted May 26, 1953.

Heretofore, efforts have been made to make use of metal carbonyls assources for metal powders but the reaction apparatus has been cloggedvery rapidly by the metal particles produced, or the reaction has been abatch type of operation, or it has been objectionable for other reasons.

The present invention has as its general object the production of metalpowders or metal strips from metals and metal carbonyls by a continuous,easily practiced method.

Another object of the invention is to avoid clogging of the apparatuswhen decomposing metal carbonyls to secure metal therefrom.

Another object of the invention is to obtain metal deposits in desiredform at relatively low production temperatures and pressures.

Another of the objects of the invention is to provide novel apparatus bywhich metals, such as iron and nickel, can be atomized by the use ofcentrifuge means alone or in combination with gas blast means.

Another object of the invention is to provide centrifuge apparatus thatcan be used for continuously producing metal particles or which can beused to produce coherent particulate metal strips, which strips are ofuniform size and gauge and exposed area.

Another object of the invention is to provide a method of continuouslyproducing a metal strip from a metal carbonyl by an efiicient, low cost,easily controlled method.

Yet another object of the invention is to obtain powdered metal fromcompounds or molten bodies thereof, while another object is to provide anew method of making metal carbonyls.

The foregoing and other objects and advantagesof the invention will bemade apparent as the specification proceeds.

For a better understanding of the invention, reference should be had tothe accompanying drawings, wherein:

Fig. l is an elevation, partly shown in section, of apparatus forpracticing the principles of the invention;

2,816,826 Patented Dec. 17, 1957 Fig. 2 is a fragmentary plan, partlyshown in section, of the apparatus of Fig. 1;

Fig. 3 is an elevation, partly shown in section, of modified apparatusfor use in performing the invention; and

Fig. 4 is an elevation on line 4-4 of Fig. 3.

The apparatus of the invention is particularly useful in the atomizationof metallic materials for the production of powdered metal and the likewhen the particles are deposited on a temperature-controlled backingbelt. For instance, a novel type of atomization of nickel, for example,or iron, for example, may be achieved by feeding the molten materialinto and through the centrifuge of the invention and through fineorifices of said centrifuge, and by gas blasting the molten metalparticles being ejected from the centrifuge of the invention to break upand further atomize and react the metallic particles. As a furthermodification of this use of the apparatus, the molten material may becaused to react chemically with the gas used to effect the furtheratomization of the particles being discharged from the centrifuge. Forexample, carbon monoxide may be used as the atomization gas and it willchemically react with molten iron or nickel being ejected in particleform from a centrifuge to form the carbonyl of such metal whichthereafter will be deposited in a precision manner upon the depositionmeans provided in the apparatus, or elsewhere, or collected as a powder.The gas blast to which the molten centrifuged particles is subjected notonly helps to break up the metal into finer particles, but produces afiner and more uniform porosity in the deposited metal strip than wouldbe attained by ordinary centrifuge action. In atomizing metal where agas blast or pressure stream is used to assist in the atomizationaction, only relatively moderate centrifugal speeds are required to keepa constant feed of small molten metal particles passing through theorifices in the centrifuge member at a satisfactory discharge speed.

In practicing the process of the invention for the production of metalstrips, it is necessary that a constant rate of atomization and depositbe achieved, so that a constant thickness of metal strip, as well asconstant particle size, is produced. Thus, molten metal or othermaterial being processed should be fed into the centrifuge at a uniformrate to maintain a uniform amount of metal therein, and the centrifugeshould be operated at a uniform speed, to maintain uniform orificepressure with a uniform gas blast. being provided for processing thematerial ejected from the centrifuge. The rate of deposition iscontrolled both by the speed of movement of the centrifuge andtemperatures at which the particles are deposited and also by orificesize and number in the centrifuge and the speed thereof when the inneropenmgs of the orifices are kept covered with processing material. Whenmetal powder is desired, the deposited particles should not contactpreviously deposited particles when any particles are still molten butif porous strips are to be produced, the newly deposited particles mustoverlap prior particles when at least the deposited particles arepartially molten.

When feeding a liquid metal carbonyl to a centrifuge, the carbonyl isheated in the centrifuge preferably to below its decompositiontemperature, and carbonyl particles are thrown from limited dischargeorifices provided in the centrifuge, and the particles discharged areusually deposited as a thin layer upon continually presented temperaturecontrolled surfaces that elevate the carbonyl particles to break downtemperature so that metal particles, or metal strip is produced from themetal carbonyl.

Suitable apparatus for practicing the invention is shown in Fig. l andit includes a crucible or container 1, having a discharge valve 2provided in the lower portion thereof for controlled fiow of a liquidmetal, or metal carbonyl that is stored in the container 1, which mayhave a top provided therefor, if desired. A rotary type centrifuge 3 ispositioned below the container 1 for receipt of liquid materialtherefrom and a receiving spout or opening 5 is provided in an upperportion of the centrifuge to receive material flowing from thecontainer. The centrifuge 3 is provided with a plurality of smalldiameter discharge holes or orifices 6 in the periphery thereof so thatthe streams of particles of the metal and, or metal carbonyl can bedischarged from the centrifuge through such discharge holes. Fig. 1shows that the orifices 6 are inclined from the horizontal axis of thecentrifuge 3 and adjacent orifices converge towards each other so thatthe materials ejected therefrom will collide to aid in breaking up theejected material into fine particles. These discharge holes 6 may beused for discharge of the liquid carbonyl after it had been heated inthe cent-rifuge to less than, its decomposition temperature, so that thecarbonyl can readily be decomposed after it has been thrown out of thecentrifuge and contacts a receiving belt or strip which is maintained ata definite temperature.

The numeral 7 is used in the drawing for indicating a porous metal stripmade from the metal particles continuously being produced by practice ofthe process of the invention in the embodiment illustrated in thedrawings and where metal is deposited as a stream of particles, theindividual particles of which contact a base in overlapping relationshipto form the metal strip 7. Usually suitable heating means 8 are providedadjacent the discharge portions of the centrifuge 3 to aid in heatingthe material being discharged completely to its decompositiontemperature so that a complete chemical reaction and break up of thecarbonyl material is assured. When molten metal is being processed, theheating means 8 may or may not be used as desired, as heating theparticles in transit maintains them at the desired degree of fluidity.The heating means 8 connect to a source of supply (not shown) of heatinggas in a conventional manner. High frequency electrical energy may besupplied to suitable inductance coils lining the discharge path of thematerial, if desired for the transit heating.

In order to accumulate and collect the material being continuouslydischarged from the centrifuge 3, a plurality of relatively narrow,discharge receiving metal bands or tapes 9 may be provided around theperiphery of the centrifuge. These bands 9 are positionedv by aplurality of suitable rolls 2 and by sprockets it which engagepositively with the inner portions of the bands 9 to drive and centerthe bands. These rolls 201 and sprocket 10 are so positioned that theendless bands 9 adjacent the centrifuge move in a direction normal to aplane defined by the centrifuge 3. The bands 9 are each provided with aflight or stretch of any desired length which is longer than thediameter of the spray field of the centrifuge 3, which flights combineto form a sub stantially continuous member around the centrifuge. Thebands 9 may be positioned any desired distance from the centrifuge 3.Gas blast nozzle means 14 may be used to aid in breaking up ordisrupting the molten particles in transit and the gas stream preferablyis at a angle to the path of the discharged particles to effect afurther break-up of the particles while they are in transit and movingacross the space between the outer side wall of the centrifuge 3 and thereceiving bands 9 and which intervening space can be convenientlyreferred. to as a treating zone. These means connect to a suitablesource (not shown) of a compressed gas, such as carbon monoxide when ametal carbonyl is to be produced, or an inert gas such as argon, whenmetal particles, are to be; produced.

Fig. 2 of the drawings clearly shows that a plurality of the metalreceiving bands 9 are provided at different circumferentially adjacentportions of the centrifuge so that the lateral margins of the bands 9substantially con- 21 tact each other to insure that relatively littlematerial discharged from the centrifuge will escape being deposited uponone of the bands 9.

Usually a motor 11 or other drive means is connected to each of thebands 9 by conventional means for driving these bands at desired andcontrollable constant linear speeds.

The provision of temperature control means for the particles depositedon the bands 9 is provided by use of a heating or cooling shoe 12positioned behind each of the bands 9 in contact therewith adjacent thecentrifuge 3 and suitable heating or cooling fluid is supplied theretoby pipes 13. If molten metal is being processed, the bands 9 are cooledfor solidifying the deposited molten metal, but if a metal carbonyl isto be deposited and be decomposed as deposited, then the bands 9 areheated prior to receipt of the liquid particles, but the bands aretemperature-controlled in any case. The flights of the bands 9 prior topassage past the centrifuge 3 may have supplemental temperature-controlmeans for the bands 9 and material thereon provided therefor, asdesired. Usually all of the positioning means associated with one band 9are carried by a suitable frame 114. These frames may be of relativelynarrow, elongate shape and may be provided with individual integralunitary supports for the different receiving units of the invention.

The deposited metal strip 7 may pass through a pair of rolls 15 prior tobeing stored on a wind-up roll 22 carried by a bracket 16. Usually themetal strips 7 are separated from the endless bands 9 on which they aredeposited by a conventional member, such as knives 21. If metalparticles are formed, they may be collected in any conventional manneras they are removed from the belts 9 by the knives 21, or they may becollected as powder, as hereinafter described. It will be appreciatedthat the relative speed or the movement of the endless bands 9 can becorrelated with the rate at which metal particles are provided by metaldeposition or by decomposition of the metal carbonyl being processed.Hence, a continuous metal strip can be produced, as is shown, or themetal powder may be collected in particle form, as explained in myco-pending application, Serial No. 40,610, depending upon the speeds ofthe bands 9 which are in relation to the amount of material beingdischarged from the centrifuge 3, both of which are constant for a givengauge of strip.

This centrifuge 3 can be rotated by any conventional means and a pulley1'? is shown engaged with a support shaft 18 provided on the centrifuge3. This pulley 17 engages with suitable driven means (not shown) torotate the centrifuge at a desired controllable rate. The centrifuge 3is suitably journaled in a bearing member 19 by the hollow shaft 18,which may be temperaturecontrolled.

In order to heat the material in the centrifuge 3, suitable heatermeans, such as burners 23, are provided below the centrifuge and theseburners 23, like the burners 3, may burn a suitable combustible gas orfluid therein, or high frequency electric heating coils may be used.

' The material received in the centrifuge 3 is supplied to it at acontrolled rate and the centrifuge will be partly filled with liquidmaterial at all operating times, as shown in the drawing. Thus, thegreater mass of material, and the greater volume of material in theccntri uge, will be positioned near the periphery thereof. Since somemetal carbonyls, such as nickel, or iron, are decomposed'at, or above,C. into carbon mono-"ride andmetal, the carbon monoxide at atomizationpxes from the apparatus as a gas which may be exhausted by conventionalmeans, and the apparatus may be operated under a partial vacuum.

Somewhat similar apparatus to that shown in Figs. 1 and 2 is shown inFig. 3, only in this instance a different shape of centrifuge is usedand a container 1 is provided which has a control valve 2" forregulation of rate of rial used for receiving liquid carbonyl thereon todecompose the carbonyl must be heated to a temperature above 180 C. andmetal, glass fiber, or ceramic fiber or quartz or other materials usedfor receiving the hot liquid are inherently of such physical propertiesas to avoid injury by being heated to the temperatures required. Theheating means used may be of any conventional type including highfrequency heating members for use with glass or quartz filaments, forexample.

The rolls may be heated to aid in effecting a cornpression action of themetal strip or metal-coated fibers passed therebetween. High frequencyelectrical energy may be used to heat the strip and densify same inconjunction with rolls 15.

In some instances, it may be desirable to feed a carrier or atomizinggas into the centrifuges 3 and 3 to be ejected from the orifices in thecentrifuges, with the material being processed.

Any foreign matter present in the metal being processed, such as metaloxides, will usually collect inside the center of the centrifuge, asthey are lighter than the metals themselves, and such foreign matter canbe removed from the centirfuge from time to time, as desired.

The openings 6 in the centrifuges of a size to pass only very finestreams of liquid therethrough, while the turbulence at openings 6permits only particles of liquid to discharge therefrom.

When covering a plurality of filaments with a metallic cover, asdisclosed in my patent application, Serial No. 722,829, the filamentsmay be passed, either singly or in groups, bundles, or yarns, through abath composed of the metal to be coated thereon, the filamentspreferably remaining in the bath long enough so that they reachsubstantially the temperature of the molten metal in the bath. In viewof the fineness of the filaments, this requires a very short period oftime. and thus the filaments may be moved continuously through the bathat a rapid rate of speed. As the filaments leave the bath, the excessmetal is removed, for example, by blowing a blast of non-oxidizing gasover the filaments or by use of an electrostatic field.

Also, the excess metal may be scraped off the filaments or removed bycentrifugal force. In any event, the filaments or fibers, when cool, areprovided with adherent sheaths or casings which are substantiallycontinuous throughout, are quite smooth and substantially im ervious,and, preferably, are of a thickness of about .0001 to .005 inch, thethickness being controllable by varying the temperature of the bath, thelength of time that the filaments are immersed therein, and otherfactors.

The coated filaments are then felted into mats which are preferablycompressed to the desired thickness and subjected to heat during thepressing operation, thereby bonding the coated filaments together attheir points of intersection. As noted above, the mats may be woven ifdesired, but this is more expensive than felting.

The mats are then cut to the desired size and shape to provide electrodeand terminal assemblies, and may be incorporated in the electrolyticdevices in the usual manner. For example, in the production ofelectrolytic condensers, two such electrode and terminal assemblies maybe separated by insulating spacers composed of papers or other suitablematerial, rolled into cylindrical form and impregnated with a suitablefilm maintaining electrolyte. Prior to assembly, one or both of theelectrodes may be subjected to a conventional electrolytic film-formingop eration such as subjecting the mat to electrolysis as an anode in asolution of borax and boric acid until the leakage current is reduced toa desired low value at a voltage above the operating voltage for whichthe condenser is intended. The completed condenser may be encased in atube in any conventional manner.

Alternatively, instead of coating the fibers and then felting them, thefibers may be felted together and then subjected to a coating operation,for example, by dipping as described above, or by depositing aluminum orother metallic vapor on the mats in a vacuum, the fibers preferablybeing heated to assure adherence of the metal sheaths. The coating mayalso be applied by a high pressure spray of aluminum in a chamber havinga nonreactive atmosphere such as described in my application Serial No.548,023, filed August 4, 1944, now abandoned, the mat preferably beingmaintained at a temperature at or near the melting point of the metalbeing deposited, thus insuring good adhesion of the molten metal and theproduction of substantially continuous sheaths on the fila ments. Also,the heat results in the excess coating metal dropping off of thefilaments while still in a fluid condition, and thus minimizes theaccumulation of coatings of undue thickness and the formation ofglobules or beads of metal. When the coating is applied to the mats inmolten form, the intersections of the filaments are bonded togetherduring the coating operation; when lower temperatures are employed, itis preferable to subject the coated mat to heat and pressure to weld orsinter the intersection as previously described.

The method of depoisting metal on the filaments from metallic vapors mayalso be applied to filaments before they are made into mats, the vaporbeing deposited either on single filaments or on groups or bundles ofseveral filaments. The vapor may be produced either by boiling themetal, preferably in a vacuum or by vaporizing the metal electrically ina vacuum, methods of this general type being well known and used in theproduction of mirrors. Other methods for coating separate filaments,groups or bundles of filaments, or mats composed of woven or feltedfilaments include coating the filaments with metal powder andsubsequently fusing the powder to provide the adherent sheath, sprayingthe filaments or fibers with aluminum in accordance with the Schoopprocess and thereafter fusing the sprayed particles preferably bypassing the coated filaments through a high frequency field, and drawingthe filaments through a die filled with molten metal and removing theexcess metal by blowing or by centrifugal force.

Where the metal is deposited in a molten state, it is preferable to heatthe filaments substantially to the melting point of the metal to securegood adhesion of the sheath metal; for such methods, therefore, it isdesirable to employ filaments composed of material which has a highermelting point than the metal to be coated.

It should be noted that the apparatus of the invention avoids anytendency to clog by the directionalized projection of the moltenmaterial released from the structure shown in Fig. 1, plus the fluidpressure exerted on the material in the centrifuge.

If desired, the filling spout 30 of Fig. 3 may be used with thecentrifuge 5 to supply molten material continuously thereto by a conduitfilled with the fluid being processed.

While several complete embodiments of the invention have been disclosedherein, it will be appreciated that modifications of these particularembodiments of the invention may be resorted to without departing fromthe scope of the invention as defined by the appended claims.

I claim:

1. That method of producing metal comprising the steps of centrifuging abody of liquid metal carbonyl, discharging liquid carbonyl particlesfrom said body as a spray stream of said particles, and heating thedischarged carbonyl particles while in said spray stream by directing aburner blast thereagainst to decompose the particles into metal and gas.

2. That method of producing porous metal strips comprising centrifuginga liquid metal carbonyl and discharging particles of tie metal carbonylas a spray stream of said particles, decomposing the discharged metalcarbonyl particles by heating the same with a burner blast while in saidstream to produce metal particles, and depositing the metal particles inoverlapping relation to produce a porous metal strip.

flow of material 4' from the container. This material passes downthrough a bore formed in an extension or discharge spout 30 of thecontainer 1*, and extends into a centrifuge 3"- on the rotating axisthereof. The discharge spout 30 is stationary and the centrifuge 3revolves around such discharge spout. This centrifuge 3 has a pluralityof small diameter discharge holes or orifices 6 provided in adiametrically disposed planar portion of the centrifuge positionednormal to the axis of rotation of such centrifuge. Any gases formed inthe centrifuge 3 may exhaust therefrom through the discharge holes 6*.

As a feature of this type of apparatus, it is adapted to be operatedunder a vacuum and especially is useful for the recovery of metalpowders or particles by ejection of the material being processed fromthe centrifuge 3 through the orifices 6 provided therein. Thus thecentrifuge 3 is shown received in a suitable, relatively large chamber31 which has a vacuum pump 32 connected thereto by a conduit 33 so that,a desired amount of vacuum can be established within the chamber 31.Usually this vacuum would be about 30 inches of mercury.

Fig. 4 of the drawings shows that a plurality of recesses 34 may beprovided in the form of channels in the inner surface of the centrifuge3 and terminate at the orifices 6 These recesses 34 have molten metal orother liquid being processed therein and flowing therethrough fordischarge through the orifices 6*. Feed of such material from aplurality of recesses to one orifice produces a turbulence in the liquidand aids in breaking up the material being ejected from the centrifugeso that small droplets and particles are formed therefrom.

The body or mass of molten metal or other material being fed to thecentrifuge normally will have a tapered or conical shape in thecentrifuge, as indicated in the drawings, it is thought. Such liquid ormolten metal within the centrifuge exerts a back pressure up through thespout 30 to the fluid material received in the container 1. The backpressure is of such value that the specific pressure of liquid withinthe container 1 does not vary the deposit action of the centrifuge andconstant operating conditions are maintained even though the level ofliquid in the container 1 varies appreciably.

Material flows to the centrifuge 3 from the container 1 at substantiallythe same rate that it is discharged therefrom after uniform operatingconditions are established in the apparatus. Usually the centrifuge 3may be about 6 inches in diameter, for example, and it would be rotatedat a speed from about 400 to 1800 R. P. M. for performing the operationsof the invention.

Fig. 3 also shows that usually the floor of the chamber 3F. has asuitable fluid 35, such as water or other material, thereover to aid incollecting the metal particles accumulating Within the chamber 31. Ifdesired, the fluid 35, which is inert to the materials being processedat the temperatures used, may be sprayed upon the inner surfaces of thewalls of the chamber 31 to aid in washing material down from the wallsto the floor where the material may be suitably collected and removed.The fluid 3.3 may be withdrawn from the container through a drain 36 andthe metal particles may be separated from the fluid at any desired time.Of course, fluid may be continually supplied to the chamber in suchinstances.

The centrifuge 3 is rotated by conventional drive means positionedexternally of the chamber 31 and engaging a support shaft 13 for thecentrifuge. The shaft 18 and spout 30 are suitably sealed where theypass through walls of the chamber 31.

It will be realized that the apparatus of the invention as shown in theaccompanying drawings may be used for building laminated metal strips,or laminations of metal on fibrous base materials, if the base stripsused are made from metal, or fibrous material and are permanently bondedto the material deposited thereon.

in practicing the invention, metals from metal carbonyls can bedeposited at relatively low temperatures so that rayon filaments, orcellulose threads, yarns, filaments, or fibers may be used in making thebase strips, while other synthetic materials or fibers may likewise beused Where the synthetic materials have appropriate chemical andphysical properties for this use.

The invention, particularly as disclosed in Figs. 3 and 4, may be usedfor decomposing titanium iodide (TiI and/or chloride, such as titaniumchloride (TiCl for obtaining titanium metal, and usually the dischargedparticles would be heated in transit to decompose the metal halide intometal and halide gas.

As has been indicated herein, the method of the invention is adaptablefor use in decomposing any metal carbonyl but it is particularlysuitable in decomposing nickel carbonyl (Ni(CO) and iron pentacarbonyl)5)- It has been established that the carbonyls referred to can bedecomposed at relatively low temperatures to secure metal therefrom. Asin the apparatus shown in Figs. 1 and 2, the apparatus of Fig. 3 can useany desired type of heating means and an auxiliary heating of thematerial being processed may occur as the material is thrown from thecentrifuge 3 in the form of rapidly moving fine particles, for example,by high frequency electric heating coils.

The metallic materials obtained by practice of the invention can be usedas the porous strip of metal produced directly by practice of theinvention, which porous strips could be used, for example, when madefrom nickel, as a storage battery electrode. The metal particles may bedeposited in sufficiently continuous form to provide coherent but porousmetal strips which have many desirable properties for use in condensers,storage batteries, or the like. The metal particles are preferably notover 8 microns in a particles maximum dimension. Of course, where spacedmetal particles are deposited on the base strips, suitable means may beused for recovering such metallic particles when separated from theendless bands on which they are deposited. The particles may bedeposited in a temperature-controlled atmosphere or in a fluid chamber,as described in my application, Serial No. 722,829 and its predecessor,application Serial No. 548,- 023, filed August 4, 1944.

Other base strips or cords or filaments may be used, such as quartzfibers, cotton, woven or matted textile or glass or ceramic fibers,paper, or other similar materials, for the bands 9 and the depositedmaterial will be retained thereon. The bands then usually would passfrom a storage reel, past the centrifuge, and to the windup reel.

The apparatus may also be used to coat metal strips with deposited metalparticles bonded thereto as a composite strip material.

Cooling means are used for the deposit belt of Fig. 1 when metal powderis to be deposited thereon, to aid in rapidly solidifying the metal ondeposit.

The various deposition means disclosed for collecting material beingejected from the centrifuges, it will be seen, are suitablytemperature-controlled.

When the apparatus of the invention is used to produce metal carbonyls,the apparatus generally would be en closed so that a carbon monoxideblast gas used may be collected and be recirculated and the apparatusmay be operated in a partial vacuum.

In feeding fluid materials from the crucible or storage containers usedfor retaining the liquids prior to passage to the centrifuge, it isnecessary that the material be fed to the centrifuge rapidly enough tomaintain the orifices in the centrifuge covered with liquid and constantuniform deposition action will be secured as long as such orifices ofthe centrifuge have complete liquid coverage. The back pressure in thespout 30 insures obtaining a proper rate of flow of material to thecentrifuge in Fig. 3.

It will be appreciated that any deposition belt or mate- 3. That methodof producing metal powders comprising the steps of centrifuging a bodyof liquid nickel carbonyl at a temperature and a pressure below itsdecomposition point, discharging heated carbonyl particles from saidbody as a spray stream, and breaking down the carbonyl particles intogas and metal particles by further heating such discharged particleswith a burner blast while in said spray stream.

4. Apparatus of the class described comprising rotary centrifuge meanshaving a centrifuge chamber for receiving molten metal, said centrifugemeans having small openings in the periphery thereof for dischargingmolten particles of said metal, receiving means located substantiallyopposite and spaced from the openings in the periphery of saidcentrifuge means for adherent deposit of said particles thereon, and gasjet producing atomization means located outside of said chamber forcausing gas jet contact with molten particles ejected from saidcentrifuge means, said jet producing means being disposed so as todirect gas jets into the intervening space between said periphery andsaid receiving means for disrupting impingement against said particleswhile the latter are traversing said space.

5. Apparatus of the class described comprising centrifuge means forreceiving molten metal, said centrifuge means having a plurality ofsmall openings in a portion of the periphery thereof for dischargingmolten particles of said metal, receiving means located substantiallyopposite and spaced from the openings in the periphery of saidcentrifuge means for adherent deposit of said particles thereon andforming a substantially continuous ring around the centrifuge means,means for moving said receiving means substantially parallel to the axisof rotation of said centrifuge means, gas jet means disposed so as todirect gas jets into the intervening space between said periphery andsaid receiving means for disrupting impingement against said particleswhile the latter are traversing said space, and means for cooling saidreceiving means.

6. Apparatus for atomizing metallic substances comprising centrifugemeans having small openings in a portion of the periphery thereofdefining a plane normal to the axis of rotation of such means, means forrotating said centrifuge means to throw out molten metallic particlesfrom the openings in said centrifuge means, a plurality of depositstrips aggregating an annular group positioned at the periphery of saidcentrifuge means with deposit receiving strip portions substantiallyopposite said openings for the adherent deposit of said particlesthereon as substantially fiat product strips, means for moving saiddeposit strips substantially parallel to the rotational axis of saidcentrifuge means past the openings in said centrifuge means, and coolingmeans located substantially opposite the periphery of said centrifugemeans and in cooling relation to said strip portions on the side of thelatter remote from said openings.

7. In apparatus of the character described, a rotatable hollowcentrifuge body having axially spaced wall portions and a peripheralwall portion connecting said spaced wall portions and defining therewitha concave internal annular pocket adapted to be supplied with fluidmaterial, means for rotating said body, said peripheral wall portionhaving discharge orifice means therein comprising an annular group ofsmall openings communicating with said pocket for discharge of saidfluid material in particle form in response to rotation of said body,and fluid material supply means for feeding fluid material to saidpocket, said supply means comprising a spout on one of said wallportions and rotatable with said body with the discharge end of saidspout extending into said pocket substantially coaxially thereof beyondsaid one wall portion and substantially to the transverse mid-plane ofsaid annular group of openings.

8. Apparatus as defined in claim 7 in which said orifice means comprisessmall openings distributed around 10 the perimeter of said body andextending in an outward= 1y converging relation from said pocket wherebyfluid streams being discharged will be broken up by impingement of thestreams against each other.

9. Apparatus of the class described comprising rotary centrifuge meanshaving a centrifuge chamber for receiving fluid material, saidcentrifuge means having small openings in the periphery thereof fordischarging fluid particles of said material, different ones of saidopenings extending in a relatively converging relation outwardly of saidcentrifuge means whereby fluid material ejected from said convergingopenings will contact to break up the material into small particles.

10. The method of atomizing metal which comprises, rotating at asubstantially constant speed a centrifuge having a chamber therein andorifice means in the peripheral wall of said chamber, supplying moltenmetal to said chamber at a rate to maintain a substantiallyconstantpressure annular fluid head of said molten metal thereinadjacent said orifice means, ejecting streams of said molten metal fromsaid orifice means, blasting said streams with gas while said streamsare in transit in space for breaking the ejected metal into smallparticles, and collecting said particles by the adherent deposit thereofon a receiving means as a substantially flat metal sheet.

11. The method of atomizing metal which comprises, rotating at asubstantially constant speed and in a substantially closed housing acentrifuge having a chamber therein and orifice means in the peripheralwall of said chamber, supplying molten metal to said chamber at a rateto maintain a substantially constant-pressure fluid head of said moltenmetal therein adjacent said orifice means, ejecting streams of particlesof said molten metal from said orifice means, collecting said particles,and maintaining a vacuum condition in said housing.

12. The method of producing porous metal strip which comprisescentrifugally discharging liquid metal carbonyl particles into andacross a treating zone as a spray stream, decomposing said particles byimpinging and heating the, same with heated gas directed into said zoneand against said particles while the latter are moving across said zone,and depositing said particles in an adherently contacting relation toform a substantially flat porous metal strip.

13. The method of producing porous metal strip which comprises the stepsof causing a forced flow of a temperature controlled fluid metallicmaterial through an orifice means for directionally projecting suchmaterial in an atomized stream into and across a treating zone,supplying heated gaseous reaction medium to said zone for a controlledheating thereof and for chemical reaction with the particles of saidstream while said particles are in transit in said zone, and depositingthe metallic product of the reaction to form a substantially flatcoherent metallic strip.

References Cited in the file of this patent &

UNITED STATES PATENTS Re. 12,568 Cowing Nov. 22, 1906 1,357,206 FullerOct. 26, 1920 1,503,960 Mackay Aug. 5, 1924 1,601,897 Wiley et a1 Oct.5, 1926 2,040,168 De Bats May 12, 1936 2,042,800 Pike June 2, 19362,061,696 De Bats Nov. 24, 1936 2,328,714 Drill Sept. 7, 1943 2,333,218Pazsiczky Nov. 2, 1943 2,439,772 Gow Apr. 13, 1948 2,497,369 PeychesFeb. 14, 1950 2,624,912 Heymes et al Jan. 13, 1953 2,646,593 Downey July28, 1953 2,698,812 Schladitz Jan. 4, 1955 FOREIGN PATENTS 571,807Germany Mar. 6, 1933 22,684 Finland Sept. 15, 1948

1. THAT METHOD OF PRODUCING METAL COMPRISING THE STEPS OF CENTRIFUGING ABODY OF LIQUID METAL CABONYL, DISCHARGING LIQUID CARBONYL PARTICLES FROMSAID BODY AS A SPRAY STREAM OF SAID PARTICLES, AND HEATING THEDISCHARGED CARBONYL PARTICLES WHILE IN SAID SPRAY STREAM BY DIRECTING ABURNER BLAST THEREAGAINST TO DECOMPISE THE PARTICLES INTO METAL GAS.